Means for controlling the cyclic operation of components of a power plant



July 11, 1950 R. J. WELSH MEANS FOR CONTROLLING THE CYCLIC OPERATION OF I COMPONENTS OF A POWER PLANT Filed Nov. 26, 1945 8,Shets-S heet 2 80M y. emu;

y 1950 R. J. WELSH 2,515,065

MEANS FOR CONTROLLING THE CYCLIC OPERATION OF COMPONENTS OF A POWER PLANT Filed Nov. 26, 1945 8 Sheets-Sheet 3 TCONTROL. DEVICE,

l N77 N76 How 'LVE. TR OVCRYA N52 u y 1, 1950 R. J. WELSH 2,515,065

MEANS FOR CONTROLLING THE CYCLIC OPERATIONOF COMPONENTS OF A POWER PLANT July 11, 1950 R. .1. WELSH MEANS FOR CONTROLLING THE CYCLE OPERATION OF COMPONENTS OF A POWER PLANT 8 Sheets-Sheet 5 Filed Nov. 26, 1945 IIIII'I-IlllllllllllllllIl-Iilllllll' July 11, 1950 R. J. WELSH 2,515,065

MEANS FOR CONTROLLING THE CYCLIC OPERATION OF COMPONENTS OF A POWER PLANT Filed Nov. 26', 1945 8 Sheets-Sheet 6 U! a, as a :z a a O gu H g f "31 as 9' 5 g 2 F a'mlll 3- 5. 0. Z'Wq 5L fi Q/Mlllll 9M1: mm: 5 MM 5 (farm/ $6M July 11, 1950 R. J. WELSH MEANS FOR CONTROLLING THE CYCLIC OPERATION OF COMPONENTS OF A POWER PLANT Filed Nov. 26, 1945 8 Sheets-Sheet 7 FIG. 7

y 1950 R. J. WELSH 2,515,065

MEANS FOR CONTROLLING THE CYCLE OPERATION 0F COMPONENTS OF A POWER PLANT Filed Nov. 26, .1945 5 s Sheets-Sheet 8 GOVERNOR VAL V5 Patented July 11, 1 95 6 MEANS FOR CONTROLLING THE GYGLIC OPERATION OF COMPONENTS OF A POW- ER PLANT Robert James Welsh, Rugby, England, assig'nor to The English Electric Company Limited, London, England, a British company Application November 26, 1945, Serial No. 630,815 In Great Britain September 10, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires September 10, 1963 4 Claims.

This invention relates to the operation of a power plant made up of a plurality of internalcombustion compressor devices of which the number in operation is variable-e. g., in accordance with the load on the plant. More particularly the invention is concerned with the control of such plant so that both the starting and the stopping of the component compressors in succession will take place in the same predetermined cyclic order e. g., the order L--MN-P--LM and so on. According to the co-pending patent application No. 546,360, new Patent No. 2,434,778 issued January 20, 1948, there is provided a plurality of start-and-stop control devices associated with individual components and adapted jointly to make connections whereby a signal can start a component at rest if it be next in cyclic order to a component which has been brought into action and another signal can stop that one of the said components in action which was first to start; each of these control devices is connected to starting and stopping devices for one component (such as M) and is influenced by the starting and/or stopping of the immediately preceding component in cyclic order (i. e., L). The above desired result is thus achieved by a combination of a number of separate control devices each associated with individual components whereby any desired power plant can be built up by taking the desired number of components each with its individual control device and appropriately connecting these devices together.

In the actual arrangement described in said Patent No. 2,434,778 there is a biassed control member-which may be a fluid-controlling valve-movable to one position or the other according to whether one particular component such as L is in action or at rest. This control member has a number of controlling ports through which is passed a starting signal'-when component L is in action-to start component M if that component be at rest and through which is passed a stopping signal-if component L be at rest-to component M if the latter be in action. Each control device such as that for component M also includes a throw-over member responsive to the starting and stopping of components L and M to ensure that when all the components are in action a stopping signal will be passed on to the first component to start-i. e. that which is next in cyclic order to the last to start.

The present invention consists of a modified control device which can achieve the same results or slightly modified results with a certain amount of simplification of the connections. According i to one feature of the present invention the startand-stop control device in association with one component such as M and the preceding one in cyclic orderi. e., component Land controlling the starting and stopping of component M is in.-

fluenced by both components L and M so as to tend to take up one position when the component M is in action and L is at rest and another .posi-'-' tion when the component L is in action and M is at rest; another such control device is similarly linked to components M and N and so on. Each of these control devices may be biassed to a third or mid position.

One form of power plant incorporating the invention and comprising a number of power components each of which is an internal combustion compressor of the known free-piston type incombination with compressed air starting means for the engine of the compressor and start-and-stop control devices therefor in the form of fluid pressure controlling valves is illustrated by the accompanying drawings of which:

Fig. 1 is a general arrangement of the complete plant, showing all the parts in external view,

Fig. 2 is a view to a larger scaleshowing the start-and-stop control devices in detail but with the compressor devices in external view but without the lay-passing devices, which are indicated in Fig. 1, v

Fig. 3 shows the addition of the automatic by;

passing devices to the arrangement according to Fig. 2,

.Fig. 4 shows a modification of the arrangement according to Fig. 2,

Fig. 5 is an enlarged detailed view of one of the compressor devices of Fig. 2, and Figs. 5a and 5b are details thereof, in section, on a still larger scale,

Figs. 6 and 7 show, also to a still larger scale two of the auxiliaries of Fig. 5 in two different positions,

Fig.8 is an enlarged section through one of the starting relays of Figs. 1 and 2, and

Fig. 9 is an enlarged section through the starting signal transmitters of Figs. 1 and 2. v

The plant is shown in Figs. 1 and 2 as comprising four similar power components LM-N and P, which are in the left-hand four of eight rectangles into which part of Fig. 1 and the whole of Fig. 2 are divided; each start-and-stop control device is shown beside one of the power components to which it is linked, in the adjoining right-hand rectangle.

Eachpower component is a free-piston internal-combustion compressor similar to L which free-piston unit consists of one of the opposedengine pistons 4 reciprocating in cylinder I a compressor piston 5 reciprocating in one of the cylinders 2 and a bufier piston '6 reciprocating in one of the cylinders 3. In the head of eachcompressor cylinder 2 is at least one inlet valve I2 which can put the cylinder 2 in communication with the suction inlet I4 and at least one discharge valve I3 which can put the cylinder 2 in communication with the conduits I5 communicating with the annular space surrounding the ring of inlet ports la in the engine cylinder I. The ring of exhaust ports I?) in the latter open into an annular space communicating with the discharge conduit I6. v v v H The reciprocating piston units are synchrofused in well known and usual manner by being linked by the pair of links 'l'to the opposite ends of the lever 8 having its mid point pivotally supported on the outside part of the engine cylinder I.

Fuel can be injected into'the cylinder I by fuel injectors 9 of conventional form supplied through fuel pipe ii, the usual form of distributor I8 and the fuel pipes I9 by the fuel injection pump it) of conventional form recipro'c'ated by cam I I which is oscillated (in accordance with the movement er the free piston units) by the bell-crank lever 20 which is connected by link 2i to a point on one of the links I. The quantity of fuel injected by each stroke of the injection pump it! is determined in the usual manner by the position of the fuel regulator Hid.-

Each buffer cylinder 3 is provided with an opening controlled by the non-return valve 22 forming an inlet valve through which compressed air can be admitted from pipe 23 for starting the engine. In addition, each buffer cylinder has a vent governed by the compression relief valve 2! which can be opened by the application of fluid pressure from pipe 26; v

A barring piston 24 movable in cylinder 25' is provided for moving the opposed piston units apart and out to the extreme outer end of their stroke on the stopping of the engine; the pistons are left in this position ready for restarting; This resetting operation is performed in response to theapplioation of fluid pressure to the cylinder 25 through resetting control pipe 26. The application of fluid pressure to pipe 26 is controlled, as hereinafter described, by the running'indicator 31, a, barring relaycomprising a valve device made up of coupled pistons 30 and 35 movable in cylinder body 32 by the application of fluid pressure thereto from pipe 33in cooperation with anfend of stroke indicator (shown enlarged in Figs. 6 and '7) comprising also a triple piston valve 34 movable in cylinder 35' and also controlled in part by the application of fluid pressure thereto from pipe 33 and partly by the action-through link 29of the opposedeng'i'ne pistons when they reach or closely approach their outer dead centre position. ,7

/ The running indicator (Fig. 511;)isj a hydrauli'c' device comprising piston valve 36' reciprocated by the link 28 in a transverse cylinder in the body 31. In a rest position such as shown, fluid pressure passes from pipe 42 through one of me two branch p'ipes 42a or 4212' past therecess 4 in one of the pistons 39, 40 to the pipe 33 and reaches, also, through pipe 38, the recessed portion of the piston valve 36, and from there, though either port 31a or (as shown) port Zib, the associated cylinder of piston 39 or (as shown) piston 40. The cylinder of the other piston, for example, of 39, as shown, is drained to exhaust into the oil sump (not shown) through its port 37a. It is clear from Fig. 5a that, if the position of the pistons 39, 40 were reversed, or both pistons were in their right hand position, the connection of pipe 33 with the pressure fluid supply from pipe 42 would still subsist.

As soon, however, as the free piston assembly is reciprocating, the piston valve 33 is oscillated through its linkconnection 28 with the free piston assemblies, and consequently sufficient fluid pressure is passed through pipe 38 round the rece's's of valve 35 and both ports 31a and t'ib to force both pistons 39 and 40 to the left against their weak springs 4|". Ports illitand 3112 are of a restricted crosssection and d'o'not allow the escapeof pressure to" exhaust intothe oil sump quickly enough toaffect the building up of pressure inside the cylinders for the pistons 39, 6. It-

clear from Fig. 5a that'in this position of the running indicatorfipipe"3'3iscut off from pipe 42; and is vented to" exhaust into the oil sump zit 37c past the recessed portions of both pistons 39', and the oblique canal 37d in the body of the casing 31'.

The fluid pressure inpipe' 33"-as soon as the engine stops-'-moves"the" piston unit 34' of the end of stroke indicator? outward to the position shown in Fig. 6*inwhich it can beoperated by motion of the free pistons andby acting on the smaller piston 38 0f the barring relay the pres sure moves this also in one direction; to" allow the fluid under pressure to'pass by way of pipe 26 to open the compression relief valves 27 in the buffer cylindersand alsoto enter theb'arring cylinder 25, thu's'causing the barring piston 24 to move outwards so as' to bear against shoulder 5a of the piston 5 and to drive the free pistons which are linked by'th'e Iin'ka'gel', 8, I to their outer dead centre position; When the free pistons" approach or reach their outer dead centre position a cam 43 actuated by them" through link 29 and the'lever 20 connected by the link 21 to the synchronising linkage, rocked about the fixed pivot 44" fro the position shown in Fig. 6 to that shown in'Figi 7 to engage a roller- 4501i the'proj'e'cting end of the piston rod of the end of stroke indicator, forcing the triple piston 34" inwards to the position shown in Figs. 5 and 7 and thereby" connecting" the fluid pressure from pipe 33' by Way of pipe 46' to a" rear part of the barring relay, behind the p stes e s which is shown as of greater a e than th'e'front piston 39 s'oth'at the forcefromthe gea will overcome that from the" front. The latter relay is'tnusmpved backto its" normal position (as; slio-wn'iriFig; 5) to disconnect pipe 23 andthe" barring cylinder 25 from the pipe as and to connect them to exhaust into the oil sump, whereby the barring piston E iis withdrawn byth' action of a, blessing force's'uch asthat' of aspr'ing l'l and'the'relief valves 2'! in the bufie'r cylinders reanreclose'. The barring piston 24, when completely: withdrawn, r'e-establishes a connection from thepipe'33' through the end of stroke'indicajtor" cylinder 35, piped-6', and ports uncovered and put into communication by the reduced points 24 0; of the piston rod of the barring piston 24to pipe 48 and a port in a starting relay 49 hereinafter described with reference to Fig. When the barring piston and co-operating parts have gone through the operations described the whole equipment is then re? set and ready for restarting, the resetting having taken place automatically in immediate response to the stopping of the engine.

The signal to restart the engine is given by the application of fluid pressure to the port 15 in the right-hand end of the cylinder 49 of the starting relay shown in enlarged section in Fig. 8; the resulting movement to the left of piston valve 50in the cylinder 49 against the force of spring 5| (which bears. against the abutment 52 adjustable by screw 53) puts the said pipe 49 in communication through pipe 54 with the cylinder 55 of the servo-motor for actuating the master starting valve 59. Movable within cylinder 55 is a piston unit made up of parts 56 and 5'! with spring 58 compressed between them; the part 57 can engage the stem of the master starting valve 59 which, when the valve is closed, rests on a seating in the valve casing 60. Provided that the corresponding running indicator 31 is in the rest position (Figs. 5 and 5a), that the end of stroke indicator 35 (Figs. 5 and 7) is in the position corresponding to the free. pistons being in the outer dead centre position and that the barring piston 24 is fully withdrawn, it will be clear that fluid under pressure can then pass from the supply pipe 42 through the pipes 33, 46, 48 and 54 to the cylinder 55 and so cause piston part 5'! to lift the master starting valve 59 off its seating. Compressed air for starting purposes from pressure pipe 6 Iwhich constitutes a source of comparatively unrestricted capacity-is hence admitted to the now closed buifer cylinders 3, by way of pipe 62, the body 63 of a timing valve provided for subsequently cutting off the air suppy to the cylinders 3, the pipe 23 and non-return starting inlet valves 22.

The timing valve 64 has three positions in the body 63, viz: (1) closed, as in Fig. 6, (2) fully open, as in Fig. '7, and (3) wholly released, as in Figs. 5 and 5!); it is biassed to position (3) by a spring 65 which holds the valve considerably clear of its seating. The valve device includes a lever 66 pivotally mounted outside the valve casing on a lug 57 extending therefrom; a trigger 68 is pivotally mounted onthis lever and normally positioned directly adjacent to the end of the stem 64a of valve 64, which stem projects through the valve casing 63. The lever 66 is biassed by gravity to a position in which the trigger 68 abuts against the valve stem 64a but the lever is free to make a small movement until arrested by a stop 61a formed by the lug 61. The onrush 'of the air entering body 63 from pipe 62 causes suction on the upper side and pressure on the lower side of the timing valve 64 itself and pressure on the under side of the collar 64?) to move it (against the biassing force of spring 65) from position (3) shown in Figs. 5 and 5b to its position (2) or fully open position, shown in Fig. '7, thus allowing air to pass by pipe 23 to the buffer cylinders 3. In position (3) a collar 641) on the valve stem 64a lying within and considerably restricting the valve-aperture acts to delay the building up of pressure on the discharge "side of the timing valve thereby accelerating 'the opening movement of this valve while at the same time delaying the initial movement of the free pistons by delaying the building up of air pressure in the buffer cylinders. This also eliminates the risk of the free pistons moving so quickly as to be beyond the correct position for cutting off the starting air before tripping the trigger as described below. The valve stem 64a, during the movement of the valve to the open position, bears against the trigger 68 which with lever 66 thus acts as a stop. The thrust of the valve stem against the trigger is on a line passing through the pivot of the trigger which therefore does not turn about its pivot but the lever 66 moves until arrested by the stop 61a. This movement of the valve and trigger, by which the valve moves to but is held in the fully open position, brings a part of the trigger 68 into the path of a part of the cam 43 actuated by the free pistons through link 29. As the pistons pass a certain point before reaching the inner dead centre position, the trigger 6B is accordingly engaged by cam 43 and turned about its pivot on lever 66 so that it releases the timing valve, allowing the latter, under the action of the air pressure, to continue its movement to the first or closed position (Fig. 6) whereby the buffer cylinders 3 are no longer connected to the pipe 62 and the pressure pipe 6|. The valve stem 64a then bears on the trigger 68 in such a way as to hold it out of the path of the cam 43 as the latter oscillates. It will be seen that the starting air supply is cut off and the timing valve mechanism does not interfere with subsequent normal operation of the free piston device. Subsequent reclosure of the master starting valve" 59 (cutting off the supply of air) allows the timing valve to return under the action of its biassing spring 65 and together with the lever 66 and trigger 68 to the wholly disengaged position so that the trigger remains out of the path of the member adapted to engage it. The movement of the free pistons will actuate the running indicator to disconnect the pipe 33 from the supply pipe 42 and connect it to exhaust into the oil sump. Pressure is thus removed from the piston unit 34 of the end of stroke indicator, which will accordingly remain in the withdrawn position and be unaffected by the subsequent operation of the engine and from pipes 46, 48 and 54 so that the pistons 56 and 51 will allow the master starting valve 59 to reclose.

Referring again to Fig. 1, the gas exhausts of the components L, M, etc. are therein designated L I 6, MIG, etc. and all discharge into the manifold 96 supplying motive fluid to the turbine 91. The latter drives, through gearing 90, the speed governor 99 which can move governor valve I00 in body IOI (shown in section in Fig. 9) to connect fluid pressure supply pipe I02 to pipe I04 on a fall in speed and the latter pipe I04 to exhaust into the oil sump through the lower opening in the valve body ID! on a rise in speed. Pipe I04 is connected to the fuel-regulating cylinders LI05, MI05, etc.

As shown in Fig. 5, each cylinder I05 contains a piston I05 movable by the fluid pressure against the force of spring it? to move the link I2 and thereby move the fuel regulator l0a. in a direction to increase the fuel supply. The engine can he stopped by temporarily cutting off the fuel supply by moving the fuel regulator I0a to the position in which the pump I0 delivers no fuel. This is done by the stopping piston 69 which can move in the cylinder body l0 (forming the stopping relay) against the force of spring II when fluid pressure is applied to the relay from pipe l4; this movement is again communicated to the fuel regulator Iila by the link 12, the pistons I06 and 69 being connected to opposite ends'of link 72. Thus it will be seen from the foregoing that-cachet the power componentslFM-N- -P can ps stopped by-the' application of a stop in impulse-t the stopping relay H! by pipe T4, the parts being automatically reset in a condition ror restarting; and each can be restarted by the application or a starting impulse to the starting re1a 49: by ipe15.

The; starting'a'nd stopping signals are applied,

to the various devices L49, L10, etc. from the startingand stopping signal lines'l B and I1 common to thewholc plant (see Figs. 1 and 2), which linesare pipes either ofwhich can-beconn'ected to-the fluid pressure supply pipe Why the signaltransmitting valve deviceis shown in section in Fig. 9.- This device includes an expansible bellows" i58 connectedtothe control pipe I04 supplying the fuel-regulating motors I135 and mechanically connected by stem III to a similar bellows I09: responsive to the pressure of the gas supplied to the turbine inl'et by being conn'ctedto manifold so adjacentthat inlet through the; pipe M61 The pressure in bellows I09 acts on bellows Illlithrough stein IIl.- A spring II2 in'a-spring' case H3 is compressed between the spring-case H2 and-thehe'ad IIIu on the stem I'II'I'; whenithespring case I I3 abuts-against the stop; II' laon the bellows case IIal the forceof spring. H2 assists the pressureof bellows I09 acting in opposition to the pressure in bellows I08, A further spring H5 in a spring-case H6 .is compressed between this spring case [I6 and headP-YII Ibi on stem III; when the spring casing HS abuts against the stop H'l'a on the bellows case HT, thefor'ce of spring H5 reduces theeffectof the opposition of the pressure of bellows '1' I09'to the pressure in bellows I08. Ihe stem III carries a' double piston valve rdeviceII8 slidable inavalve body I] e to-either side of'a normal position';

Wh'en the pressure of the fiuid suppliedto the fuel regulating.cylinders IE5 by pipe I64 exceeds a predetermined.value, which depends upon'the pressure in bellows its. and which accordingly increases with increase in: the gas pressure in m'anifoldzllfi; the: bellows I53 can move thest'em I I I and valve device II8 against the combined iorceofthe spring H2 and bellows I09 and thereby; connect the fluid pressure supply pipe -18 to thestarting signal line it and so give a starting signal. When; on the other hand, said fluid pressure applied to the fuel regulating cylinders Hi5 by pipe 6% falls below a predetermined: value (which value again increases with increase in the gas pressure in manifold 96) ,the force applied tothe stem I II by the: bellows I39 exceeds the force applied by the bellows 1'08 and so can move the stem Ill and valve ll't'to connect the pipe '73 to the stopping signal line 11. If device l9 were not responsive to the gas pressure in manifold 96, then another compressor would be started each time the fuel supply per gas generator is increased above a certain fixed value. Similarly, a gas generator would be stopped'each time the adjustment of the fuel regulators decreased the fuel supply per compressor below a certain fixed value. Such an arrangement would not operate the plant to the best-advantage; At constant piston stroke and speed thepoweroutput of a free-pistoh compressor varies in the samesense as the output pressure but not necessarily in direct proportion --there'tc; thus the maximum output of a single compressor working at a somewhat low pressure is less than when it is supplying gas in common withothers at a higher pressure and hence the.

fuel supply can-be increased only'to avalueless than that corresponding to:fullload and DOSSi-r bly to less than"v that corresponding to optimum load. If the successive starting and stopping of OOIYlPIGBSSOISYOCCLllS. always at the samerfuelzadjustment this will be limitedto a point not'exseeding. that corresponding ,to the-maximum possible fuelsupply tora single compressor working at minimum pressure whereas for working under most economical conditions it will usually be advisable to raise'the starting or stopping point or both as increase inpressure makes this possible. This is achieved with the device described, which is actuated differentially inaccordance with fuel adjustment and gas discharge pressure,.so that thestarting or'stopping. signal is given at a value ofiuel' supply per compressor which increases with increaseofgas discharge pressure.

When one compressor alone is operating,.the fuel supply thereto is progressively increased in response to increase in the load on the turbine until; at some fuel supply a: less than the maxi.- mum the fluid pressurein the bellows I08 is sufliicient' to cause a, starting signal and a second compressor is started. Theturbine speeds up,.the governor Qtrespond's and the fuel supply to both compressors, is immediately decreased but will again increase on further increase in load: on the-turbine; owingv to: theincrease in gas pres+ sure in bellows 5839' the fuel'supply to eachcompressor'in action mustbe increased to a value greater than :1: and the fluid pressure in the bellows i d 8 increased to a correspondingly higher value before another starting. signal is given, .and soon. When all or nea'rly all:oi:the compr.essor devices are in operation, supplying; anearly fully loaded-turbine at high pressure, a decrease int-he fuel supply compressor to a value 2 will cause a stopping signal to be given whereas, owing.v to the-decreasein-gas pressure'in bellows" Iil9-,.the next stopping signal will not be given untilthe fuel supply is less than 2,. and. so on. The-two springs. H2 and H5 facilitate separate adjust"- ment of the iuelsupplies at which startingand stopping. signals are given. 1

The governor'llll asshown inFi'g. 1,. is loaded by spring I21 and includes a speedadjuster comprisinga piston 'll2-I movable in cylinder I22to which is applied, through pipe III), the pressure in the-manifold 9G in opposition to the force of loading spring. I20. Thus the speed at which the governor bringsthe valve; :IBI to its mid-positionive, the speed'at which the governor tends to keep the turbine running-is controlled by this speed-adjuster and is decreased with. increase in the pressureof the motive gas supplie to the turbine.

The connecting lines from the starting, and stopping-signal lines. It and TI to the starting and stopping devices are controlled by the control devices L83, M83, etc., in such manner that the power components will start in cyclic order- LP-M--N-P--LM, etc., in response to successive starting signals or one long-sustained starting. signal and will stop in the same cyclic order m response to separate stopping. signals or one longsustained-stopping signaLthe first to start being thus also thefirst to stop.' The control devices are all alike, ascan be. seen in Eig. 2. Control device L83, for-example, consists of-a cylinder: and also a piston valve L84 movable in the-cylinder of L83 to either side of amid-position. Fluid pressure from the runningindicator- L31, when :component L is at rest,.:is.ap-

plied through pipe L33 to the left hand end of cylinder L83 tending to "move the piston valve L84 therein to the right, from the position in which it is shown, against the force of a biassing spring L85 which tends to return the valve M84 to the mid-position. Fluid pressure from the running indicator L31 is applied through pipe L83 to the right hand end of cylinder M83 when component L is at rest, tending to move the piston valve M84 to the left into the position corresponding to in which L84 is shown and in which it will stay unless acted on solely by pressure from the running indicator M31.

The devices are shown as if L is at rest, M and N in action, and P at rest. Thus since component P is at rest and the preceding component N is in action, piston valve P84 is in the right hand position. Starting relay P49 is accordingly connected through pipes P13 and P16 to the starting signal line 16. Thus when the next starting signal is given to starting signal line 16, component P will receive this signal and should start. In response to the starting, the running indicator P31 will cut oil pressure from the left hand end of the cylinder P83 and there being no fluid pressure applied to either end of the piston P84 the biassing spring P85 will return the piston to its mid-position in which both the starting relay P88 and the stopping relay P are cut oil from the starting and stopping signal pipes 18 and 11.

Also since component M is in action and the preceding component L is at rest, fluid pressure from the running indicator L31 will be applied to the right hand end of cylinder for M and the valve M84 will be in the left hand position connecting the stopping relay M10 through pipes M14 and M11 to the stopping signal line 11 so that the next stopping signal will go to the relay M18 and component M should accordingly stop and cause its running indicator M31 to apply pressure to the left hand end of cylinder M83 through pipe M33. There will now be equal pressures on opposite ends of piston valve M84 and since there is no biassing force to return the piston from its left-hand position, it will remain in this position until the subsequent starting of the preceding component L; in this condition prior to the starting of component L the control device can pass on subsequent stopping signals ineffectively and harmlessly to stopping relay M18 of component M. The subsequent starting of component L will cause pressure to be removed from the right-hand end of piston M84 so that the pressure on the left hand end will move the piston from the left-hand position to the right-hand position.

Consider again the condition in which component M is in action and the preceding component L is at rest, the piston valve M84 being in the left-hand position, but before the next component N has started. .On the subsequent starting of the component N the valve N84 will return to the mid-position in which it is shown, and so on for the other components P L as they start in cyclic order. The valve M84 will remain in the stopping position even after the starting of component L; the latter event will remove pressure from the right-hand end of piston valve M88 which will then have no force acting on it and will remain in position. All the power components will now be in action but only this one piston valve M84 will be in the left-hand position ready to pass on a subsequent stopping signal to the componentM. Thus with the components starting one by one, the starting of the last component will leave the control equipment ina position in which the next in cyclic orderi. e., that component which was the first to start-will be the one to receive the next stopping signal.

Patent No. 2,434,778 also describes provision whereby a stopping signal is elleotive to stop a component only if the next component in cyclic order is in operation, this ensuring that a stopping signal is ineffectiveif there is only one component in operation. This can be achieved with the arrangement according to the present invention by including an extra valve part L84", M84" on each of the piston valves, as shown on the devices L83, M83 in (Fig. 4, and by a pipe connection L114, M114 between adjacent devices L83, M83, etc. This valve part is closed only when the piston is in its right-hand position,- in similar fashion to the valves described in Patent No. 2,434,778. A signal to astopping relay such as L18 from line L11 has to go by way of line L14 and valve L84 in the device L83 and through line Ll14 to the valve MM in the device M83, and when component M is at rest this extra valve is closed to prevent-the transmission of the stopping signal by line L14 to the stopping relay L18 for component L. With this arrangement the plant can be shut down only by stopping the last of the components by moving its regulator 18a by hand to the no-fuel position. When the plant has thus been shut down, it "can be restarted by moving one of thestarting relay members 50a (Fig. 8) by hand. I

If the biasing springs L15, M85, etc., of the arrangement according to Fig. 2 be omitted, each piston valve 84 will then'be such that it will occupy either its left-hand or its right-hand position; this will result in the transmission oi a starting signal to a'component already in action, which generally will be harmless. Stopping signals will shut down the whole plant by stop?- ping the last power-component in action, buta subsequent starting signal will automatically start that one of the components which hasbeen longest at rest, i. e., the one-next incyclic order to the last to stop. l

The addition to Fig. 2 of means for putting any one of the components L, M etc., entirely out of action without interfering with the cyclic operationof the rest of the plant is shown partly diagrammatically in Fig. 3 in which however the construction of a by-passing throw-over valve N86 for component N is shown in section. Each component has a similar valve. Normally, running indicator L31 is connected through pipe L33, not directly to valve M83 as in Fig. 2, but through valve L88, pipe L81, valve M88 and pipe L88 to valve M83, the connections inside the valves L86 and M88 being indicated in Fig. 3 by dotted lines. Similarly, running indicator M31 is normally connected to pipe M88 and valve N83, etc. 'In-elTect the connections are then precisely as in Fig. 2. The valve device N88 has therein a piston valve N89 biased to the right-hand position by spring N98.- In this position the throw-over piston valve'N89 completes the connections between pipes N33 and N81, and pipes M81 and M88 for normal operation as described. In the left-hand position in which throw-over valve P88 is diagrammatically represented, the running indicator N31 is disconnected from control device P83 and directly connected to control device L83 by the connection togetherof pipes N81 and P81 as shown by the dotted line.

7 Throw-over valve N86 may be manually operatedand'moved to the left by handle N91 serving also asa latch) when it is desired to wit power component N 'out :of action for examination. Valve P86 is shown latched in'this position. In addition, the throw-over valve N86 may be 'moved. from right to left if, after a time delay, power componentN fails to start on receipt of a starting signal, so that control device N83 willb'e cut out of "circuit after a suitable lapse-of time and power component 1? brought into service.

On failure of a component such as N to start in response to the application of a starting signal thereto from line '16 this signal will remain applied 'foran abnormal time. The movement of starting relay N49 (see also Fig. 8) connects p'ipe's N 33 and N92 so causing fluid pressure from running indicator N31 to be applied through pipes N33 and N92 and through a restricted orifice N93 to one end of a pistonN9'4 actuating piston valve N89. This piston N94 thus moves so slowly against the biassing force of spring N90 and has a strokeoi such length that if component'N makes a promptstart the piston N94 and valve N89 do not move far before the pressure is cut off by the running indicator N31 and the piston is returnedby the spring'N90. But if *after a certain time the component N'has failed to start, the 'p istonN94 and throw-over piston valve N89 will have moved to a position in which the valve is 'heldby latch N9'!to cut out the starting and stopping arrangements for the component N and pass on the starting signal to the next component P. 'This' is accomplished by means of a port N86" connecting the recessed valve portion between the "pistons N94 and N89 with the recessed valve portion between the valve-pistons N89" 'a'n'd'N89'. Wh'en'the Valve p'istOnN89 'is inthe left hand position and held there 'by means of the latch N91," the port N86" connects the pipes N33 andlvl88. This allows -i:'ir '=,'s si1ie from the running indicator N3! to be applied to the right hand-end f the throw-over piston valve N84 (Fig. 2). There are"thus now equal pressures at each end of' thepiston valve N84 which is accordingly moved "to the neutral position by the spring NBS, thereby cutting out the starting and stoppin signalling lines N16 a'n'd'N'l'l respectively. The valve can be reset by releasing the latch N9! by hand If a com- 'po'nentin action'should stop, 'due to afault, and the supply to the turbine is decreased, the governor will give a starting signal to start that component which is the'neiit due to start. 'When the due course ofcyclic'operation it becomes the turn of the faulty component tostart'in response to a starting signal, it'will probably not start and then the appropriate byp'assing throw-over valve device :86 will act.

WhatI claim as my invention and desire to "secure -by Letters Patent is: Y

1. Power plant comprising in combination a plurality of internal-combustion compressor devices, a starting device and a stopping devicei'or each of said compressordevices, a starting signal s top signal transmitter connected to said signal lines, means for applying to said transmitter an actuating force in accordance with the setting of said fuel regulatorsand means for'ap'plyin'g 1 2 an opposing force to said transmitter proportional to the gas dischargerpressure from said compressors. f

2."Power plant comprising in combination a prime -m'over,=;a plurality of :internal-combustion compressor devices with their outlets connected in-common .to the inlet to said-prime mover, a starting device: and a stopping device for each of said compressors, a starting signal line, alstopping. signal-line, means iorlconnecting the starting andv stopping devices of the various compressors selectively andsequentially to the starting and stopping signal lines respectively, i-uel regulators .for said compressors :spring-'biassed towards the no-:fuel position, fluid pressure motorsacting on said regulators :in-opposit-ion to the biassing force, a speed governor driven :by the prime mover, .a-control valve for said [fluid-pressure motors 'actuatedzby said governor, a start-'- and stop signal -.transmitter connected -to said signal :lines, actuating means for. said transmitter responsiveato the-pressure of the fluid in said fluid-pressure :motors and opposing means .responsive to the pressure of "the gas going to said prime uncover from the compressors.

3. Power-plant comprising in combination a prime mover, a plurality of internal-combustion compressor devices with their outlets connected incommonto the inlet tosaid, prime mover, a speed governor ,driven by the prime mover, fuel regulators for said compressors under the control. of said governor, :means for starting and-stopping said compressor devicesin sequence in response to starting and stopping signals, means'for transmittingsaid signals: under .athe control of said governorandlmeans for increasing with increase of gas discharge pressurefrom said compressors the value of fuel supplypercompressor device at which starting and stopping of ,each compressor device in succession occurs.

4. Power plant comprising in combination a prime mover, a plurality of internal-combustion compressor devices with 'their outlets connected in common "to the inlet to :said prime mover, speed'governor jdriven by the tprime mover, fuel regulators for said compressors, actuators for said fuel regulators, signal means moved by'said governor for setting said actuators in motion when the prime'mover speed rises above'and falls belowa predetermined value, means for decreasing said predetermined value of speed with increase "in 'gas'discharge pressurerfrom said compressors, second signal'transmitting means yresponsive tothe said signal means move'd'by said governor, means for starting and stopping said compressor devices in response to signals from said sec'ond'signal meansandmeans for increasing withfincrease of gas dischargepressure from said compressors the value 0f fuel supply per compressor device at which said second signal device gives signals.

"ROBERT JAMES REFERENCES cnrni) The following references are-of record in the file of this patent:

UNITED "STATES PATENTS Number Name Date 2,423,472 Welsh July 8, 1947 2,434,778 Welsh Jan. 20, 1948 FOREIGN PATENTS Number Country 'Date 467,561 Great Britain June 14, 1937 183,759 Switzerland July 16,1936 

